Logging function write_log() for debugging process

helpers-write-log.php

// -----------------------------------------------------------------------------

/**
 * Logging to debug.log in DEBUG_LOG_DIR dir (default is the root site dir)
 *
 * Note: You can define in the wp-config.php:
 * 1) define( 'DEBUG_LOG_DIR', dirname( __FILE__ ) . '/' );
 * 2) define( 'DEBUG_LOG_INVERTED', false);
 *
 * Author K
 * Version 2.0.1.0
 */
if ( ! function_exists( 'write_log' ) ) {
  function write_log( $log = null, $before = '', $after = '', $clear = false ) {
    if ( true === WP_DEBUG && ( defined( 'DEBUG_LOG_DIR' ) || defined( 'ABSPATH' ) ) ) {
      // Destination File
      $debug_log_file = ( ( defined( 'DEBUG_LOG_DIR' ) ) ? DEBUG_LOG_DIR : ABSPATH ) . 'debug.log';
      // Clear debug.log if 'true' or the file is more than 10Mb (10485760 bytes)
      if ( true === $clear || filesize( $debug_log_file ) > 10485760 || ! file_exists( $debug_log_file ) ) {
        file_put_contents( $debug_log_file, '' );
      }
      if ( is_writable( $debug_log_file ) ) {
        $content = '';
        // Only string can be in the wrapper role
        $before = is_string( $before ) ? $before : '';
        $after  = is_string( $after ) ? $after : '';
        // Build content ('-' & 'hr' define a separate line before the content)
        $hr      = in_array( $clear, [ '-', 'hr' ], true ) ? str_repeat( '-', 80 ) . PHP_EOL : '';
        $content .= date( 'Y-m-d H:i:s' ) . ': ' . $before . var_export( $log, true ) . $after . PHP_EOL;
        // Write log
        if ( defined( 'DEBUG_LOG_INVERTED' ) && false === DEBUG_LOG_INVERTED ) {
          $content = $hr . $content;
          file_put_contents( $debug_log_file, $content, FILE_APPEND ); // was (temp): error_log( $content, 3, $debug_log_file );
        } else {
          $content = $content . $hr . file_get_contents( $debug_log_file );
          file_put_contents( $debug_log_file, $content );
        }
      }
    }
  }
}

// -----------------------------------------------------------------------------